1. Technical Field
The present invention relates to a projector.
2. Related Art
There is a known projector including a light source apparatus, a light modulator that modulates light outputted from the light source apparatus in accordance with image information, and a projection system that projects the light modulated by the light modulator. Further, there is a proposed projector using a laser light source, for example, for the purpose of prolonging the life of the light source apparatus (see JP-A-2012-83695, for example).
The projector described in JP-A-2012-83695 includes a light source apparatus having a laser light source that emits blue light (excitation light), a light emitting device, a color separation system, liquid crystal light valves provided as light modulators for three types of color light (blue light, green light, and red light), a light combining element, and a projection system.
The light emitting device has a function of transmitting part of the blue light emitted from the laser light source and absorbing the remainder of the blue light and converting it into yellow light.
The liquid crystal light valve for blue light modulates the blue light emitted from the laser light source. The liquid crystal light valve for green light and the liquid crystal light valve for red light modulate green light and red light emitted from the light emitting device and separated by the color separation system. The light beams modulated by the liquid crystal light valves are combined with one another by the light combining element, and the combined light exits out of the projection system.
However, in the technology described in JP-A-2012-83695, in which the blue light emitted from the laser light source is narrow wavelength band light, interference fringes can be produced in the display area of the liquid crystal light valve irradiated with the blue light. That is, since a liquid crystal light valve has a multilayer structure in which a pair of substrates, electrodes, a liquid crystal material, and other components are stacked on each other, part of light incident on the liquid crystal light valve is reflected off the members described above and experiences multiple beam interference, and the optical spectrum of the light reflected off the liquid crystal light valve shows a phenomenon in which small amplitude waves are continuously produced (ripple). The reflected light, the intensity of which at a wavelength varies in accordance with variation in the thickness of each of the members that form the liquid crystal light valve, produces a ripple that causes optical intensity at the same wavelength to vary in accordance with the variation in the display area. As a result, at the wavelength of the light emitted from the laser light source, a portion where the reflected light has high intensity and a portion where the reflected light has low intensity are produced in the display area of the liquid crystal light valve, undesirably resulting in interference fringes in the display area of the liquid crystal light valve and hence brightness unevenness and color unevenness in a projected image.